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struct type ptr

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Richard Russell
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Re: struct type ptr
« Reply #15 on: Nov 19^th, 2015, 4:51pm »

on Nov 19^th, 2015, 4:17pm, pnlawrence wrote:

Mr. Gundel needs to hire me to be his "bumbling around and finding problems" guru. cheesy

Although you probably don't want a serious answer to a frivolous post, there's little evidence that Carl cares. angry

In 'updating' LB from 4.04 to 4.5.0 he has failed to address the majority of bugs recorded at the Liberty BASIC Bug Tracker Wiki. I would have expected him to go through that list and either fix every bug or explain why he is unable or unwilling to do so. I am prepared to accept that some bugs may be considered insufficiently important to warrant the time and effort it would take to fix them, and even that some are impractical to fix because of limitations in his tools, but we should be told that.

Instead, major bugs (like TIMER being unable to use a SUB handler) remain unfixed in LB 4.5.0 with no explanation.

Richard.

« Last Edit: Nov 19^th, 2015, 4:53pm by Richard Russell »

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joker
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Re: struct type ptr
« Reply #16 on: Nov 19^th, 2015, 5:19pm »

After trying to compile the previous code in LB, the compiler error message related that CHAR[12] is an illegal type.

Not a type and not even a reserved word.

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joker
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Re: struct type ptr
« Reply #17 on: Nov 19^th, 2015, 5:26pm »

I would like to do something like this:

Code:

function WriteINIStruct1(SectionName$,KeyName$,KeyChars$,inifile$)
    ' Returns true (1) if nothing wrong or false (0) if a problem
    'code by Richard Russell
    size = len(KeyChars$) * 2 + 1
    struct structName, keychars$ as CHAR[size]
    structName.keychars$.struct = KeyChars$
    size = len(structName.struct) 
    calldll #kernel32, "WritePrivateProfileStructA", _ 
    SectionName$ as ptr, _  ' Section name 
    KeyName$ as ptr, _    ' Key name 
    structName as struct, _   ' Structure 
    size as ulong, _      ' Size of structure 
    inifile$ as ptr, ret as long
    WriteINIStruct = ret
end function

However, LBB seems to choke on this with a "struct not defined error". Either I can't define the struct within the function or it doesn't like the variable within the CHAR[ statement. I can't tell which.

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Richard Russell
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Re: struct type ptr
« Reply #18 on: Nov 19^th, 2015, 5:42pm »

on Nov 19^th, 2015, 5:19pm, pnlawrence wrote:

After trying to compile the previous code in LB, the compiler error message related that CHAR[12] is an illegal type.

I don't get an error message from either LB 4.04 or LB 4.5.0 with the code I listed. Are you definitely using exactly the code I listed in my earlier post?

Quote:

I would like to do something like this:
Code:

struct structName, keychars$ as CHAR[size]

You can't. LB and LBB must know the size of the STRUCT at compile time, so you can't specify something like CHAR[size] because then the size is known only at run time. This is quite normal in other languages too.

You should specify whatever the maximum required size is, so if your string has a maximum length of 255 characters specify CHAR[256] (including the terminating NUL).

Richard.

« Last Edit: Nov 19^th, 2015, 5:53pm by Richard Russell »

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joker
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Re: struct type ptr
« Reply #19 on: Nov 19^th, 2015, 6:39pm »

I probably had the CHAR[size] code in the first trial. I know where to go now.

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joker
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Re: struct type ptr
« Reply #20 on: Nov 21^st, 2015, 12:43am »

I can make this code operate, but I can't make the "Get" work as a FUNCTION by returning the value. I had to pass a variable BYREF. It works, but wasn't my goal.

I speculate that since I am passing the STRUCT name that the FUNCTION is working on a copy of STRUCT. Interesting.

Any ideas on returning the STRUCT value with a FUNCTION?

Also, I found out that CHAR[10] really only stores a string of 9 characters. I guess the rest is overhead? I don't understand why specifying [10] in the code doesn't save 10.

OUTPUT LOOKS LIKE THE FOLLOWING:

Code:

[settings]
config=30313233343536373839000D

Code:

if right$(DefaultDir$,1)<>"\" then
    DefaultDir$=DefaultDir$+"\"
end if
inifile$ = DefaultDir$ + "JunkINIstruct.ini"

print inifile$

struct structName, keychars$ as CHAR[11] ' if CHAR[10] you can only write 9 characters

ret = WriteINIStruct1("settings","config","0123456789",structName,inifile$)
print "ret from write: ";ret

'structName.keychars$.struct = ""
'print "test struct clear: "+structName.keychars$.struct

ret = GetINIStruct1("settings","config",GetKeyChars$,structName,inifile$)
print "ret from get: ";ret
print "Got this: ->"+GetKeyChars$+"<- (from GetINIStruct1)"

end

function WriteINIStruct1(SectionName$,KeyName$,KeyChars$,structName,inifile$)
    ' Returns true (1) if nothing wrong or false (0) if a problem
    'code by Richard Russell
    structName.keychars$.struct = KeyChars$
    size = len(structName.struct) 
    calldll #kernel32, "WritePrivateProfileStructA", _ 
    SectionName$ as ptr, _  ' Section name 
    KeyName$ as ptr, _    ' Key name 
    structName as struct, _   ' Structure 
    size as ulong, _      ' Size of structure 
    inifile$ as ptr, ret as long
    WriteINIStruct1 = ret
end function

function GetINIStruct1(SectionName$,KeyName$,byref GetKeyChars$,structName,inifile$)
    ' Returns true (1) if nothing wrong or false (0) if a problem
    'code by Richard Russell
    size = len(structName.struct) 
    calldll #kernel32, "GetPrivateProfileStructA", _ 
    SectionName$ as ptr, _  ' Section name 
    KeyName$ as ptr, _    ' Key name 
    structName as struct, _   ' Structure 
    size as ulong, _      ' Size of structure 
    inifile$ as ptr, ret as long
    GetKeyChars$ = structName.keychars$.struct
    'GetINIStruct1 = structName.keychars$.struct ' this won't work. "Type mismatch" error.
    GetINIStruct1 = ret
end function

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Richard Russell
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Re: struct type ptr
« Reply #21 on: Nov 21^st, 2015, 03:35am »

on Nov 21^st, 2015, 12:43am, pnlawrence wrote:

I can't make the "Get" work as a FUNCTION by returning the value.

I wonder if the problem is as simple as forgetting that a function which returns a string must itself have a name ending in a dollar. So for example the function might be called GetINIStruct1$().

Quote:

I speculate that since I am passing the STRUCT name that the FUNCTION is working on a copy of STRUCT.

STRUCTs in Liberty BASIC are always global. You cannot pass a struct as a parameter to a SUB or FUNCTION. Is that what you were hoping to be able to do?

Quote:

I don't understand why specifying [10] in the code doesn't save 10.

You berated me the other day for not reading all of your messages, now you're not reading all of mine! I wrote: "strings stored in a CHAR member are assumed to be NUL-terminated ... so CHAR[12] will hold at most an 11-character string."

Richard.

« Last Edit: Nov 21^st, 2015, 04:07am by Richard Russell »

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tsh73
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Re: struct type ptr
« Reply #22 on: Nov 21^st, 2015, 03:57am »

Quote:

Also, I found out that CHAR[10] really only stores a string of 9 characters. I guess the rest is overhead? I don't understand why specifying [10] in the code doesn't save 10.

ABS of API#5 says
Quote:

The GetWindowTextA function also requires an argument that specifies the length of the string buffer. We can get the length with the LEN() function, like this:

length=len(Caption$) + 1

We add 1 to the length argument because Liberty BASIC adds a null termination character to strings passed into API calls.

Also, wikipedia::Null-terminated string

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joker
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Re: struct type ptr
« Reply #23 on: Nov 21^st, 2015, 08:51am »

Ok, ok. At least I only make simple mistakes. rolleyes

The old "$" specification problem. The error message was telling me, but I wasn't listening.

I thought I tried struct as GLOBAL but ... Oh well, I have an eye doctor appointment coming up. embarassed

The last character at the end of the OUTPUT (in Notepad) looks like a "D" I haven't looked at it with anything else. I was thinking how did a CR get there?

PS. Richard, I don't "berate". I just gently "chide." cheesy

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joker
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Re: struct type ptr
« Reply #24 on: Nov 21^st, 2015, 09:15am »

I remember now.

tsh73 posted (on that "other" forum) that the API puts a CHECKSUM on the end.

The last 2 bytes are the checksum. (The least significant byte of the sum of all the ASCII values.)

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joker
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Re: struct type ptr
« Reply #25 on: Nov 21^st, 2015, 09:39am »

I found out that CHAR[32766] is the largest that works with the API (or is it a limit of CHAR[]?) That's plenty of room for INI stuff. I suppose there's a problem with running out of something while the program is running if the STRUCT gets too large.

Its a little clunky, because the name of the STRUCT is coded into the FUNCTION, but I envision several specific FUNCTIONs with several specific STRUCTs writing to the same INI file.

Maybe obfuscation isn't so clunky after all? :D

Code:

if right$(DefaultDir$,1)<>"\" then
    DefaultDir$=DefaultDir$+"\"
end if
inifile$ = DefaultDir$ + "JunkINIstruct.ini"

print inifile$

struct structName, keychars$ as CHAR[32766] ' fails when CHAR[32766] is exceeded

ret = WriteINIStruct1("settings","config","0123456789:",inifile$)
print "ret from write: ";ret

print "Got this: ->"+GetINIStruct1$("settings","config",inifile$)+"<- (from GetINIStruct1$)"

end

function WriteINIStruct1(SectionName$,KeyName$,KeyChars$,inifile$)
    ' Returns true (1) if nothing wrong or false (0) if a problem
    'code by Richard Russell
    structName.keychars$.struct = KeyChars$
    size = len(structName.struct) 
    calldll #kernel32, "WritePrivateProfileStructA", _ 
    SectionName$ as ptr, _  ' Section name 
    KeyName$ as ptr, _    ' Key name 
    structName as struct, _   ' Structure 
    size as ulong, _      ' Size of structure 
    inifile$ as ptr, ret as long
    WriteINIStruct1 = ret
end function

function GetINIStruct1$(SectionName$,KeyName$,inifile$)
    ' Returns string value if nothing wrong or NULL if a problem
    'code by Richard Russell
    size = len(structName.struct) 
    calldll #kernel32, "GetPrivateProfileStructA", _ 
    SectionName$ as ptr, _  ' Section name 
    KeyName$ as ptr, _    ' Key name 
    structName as struct, _   ' Structure 
    size as ulong, _      ' Size of structure 
    inifile$ as ptr, ret as long
    if ret = 0 then GetINIStruct1$ = "" : exit function
    GetINIStruct1$ = structName.keychars$.struct
end function

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Richard Russell
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Re: struct type ptr
« Reply #26 on: Nov 21^st, 2015, 10:00am »

on Nov 21^st, 2015, 09:39am, pnlawrence wrote:

I found out that CHAR[32766] is the largest that works with the API (or is it a limit of CHAR[]?)

I'm really not sure what you are trying to achieve. If you are storing a single string, especially if it is quite a long string, using a STRUCT isn't a particularly appropriate method. For example it stores more than twice as much data in the INI file as it needs to (each character of the string gets expanded to two hex characters).

If your objective is to obfuscate the string, storing it as hex will defeat only the most simplistic attempts at reading it. Many people will immediately recognise hex text, and either be able to read it 'by inspection' or simply copy-and-paste it into their favourite hex editor.

A trivial encryption technique, like XOR-ing each character of the string with a pseudo-random key, would be much more effective and not waste space in the file. STRUCTs wouldn't be involved at all.

Richard.

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joker
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Re: struct type ptr
« Reply #27 on: Nov 21^st, 2015, 10:46am »

Not concerned with file size. "Many people" are not part of my target audience. Some folks just think its fun to poke around and see what they can do.

Also, I like it that the "fields" of the STRUCT are not delineated in the file.

Of course one wouldn't write a 32K section to an INI file, but that is a tested limit.

I used the word "obfuscation" instead of "encryption" for a reason. Not even trying to hide it in plain site.

If the STRUCT(s) look like the following, then I think the INI file data would be obscured well with little programming effort. And there's the checksum, although that's not much of a deterrent, to contend with if one just changes a character.

Code:

STRUCT startup, keychars$ as CHAR[12], numUsers as long, posX as ulong, posY as ulong, mainDataFilename$ as CHAR[32], thumbDrivePresent as boolean, screenSizeHeight as ulong, screenSizeWidth as ulong

STRUCT currentUser, userName$ as CHAR[12], userDescription$ as CHAR[257]

Write these in separate sections of an INI file, and Bob's your uncle. (Bob is your uncle, isn't he? :D )

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joker
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Re: struct type ptr
« Reply #28 on: Nov 22^nd, 2015, 12:21am »

Posted the following to the other forum, too.

My version using FUNCTIONS. (Thanks to R.R. and tsh73 for debugging.)

Code:

'===========================================
' WritePrivateProfileStructA Demo
'===========================================
' Acknowledgements to the original authors
' Submitted by pnlawrence 11/21/2015

' This is only one example on how to perform INI file Section writing with a STRUCT. 
'   Of course, the STRUCT(s) can be rewritten and the FUNCTION(s) 
'   can be slightly rewritten to return almost any INI file data.

if right$(DefaultDir$,1)<>"\" then
    DefaultDir$=DefaultDir$+"\"
end if
inifile$ = DefaultDir$ + "JunkINIstruct.ini"

print inifile$

' STRUCT can be created however required with many different types included
'   nothing in the resulting INI file section delineates the different parts of the STRUCT
'   the resulting INI file section also includes a checksum to detect changes
'   the resulting INI file section is more than double the original total length of the values written
'       because each input character string/value is written as double-digit ASCII + nul termination + checksum
'   the STRUCT is GLOBAL

struct structName, keychars$ as CHAR[12] ' fails when CHAR[32766] is exceeded

print "Return from write: "; WriteINIStruct("settings","config","0123456789:",inifile$)

print "Return from get: ->"+GetINIStruct$("settings","config",inifile$)+"<-"

end

'===========================================
'   FUNCTIONS
'===========================================

function WriteINIStruct(SectionName$,KeyName$,KeyChars$,inifile$)
    ' Returns true (1) if nothing wrong or false (0) if a problem
    'code by Richard Russell
    structName.keychars$.struct = KeyChars$
    size = len(structName.struct) 
    calldll #kernel32, "WritePrivateProfileStructA", _ 
    SectionName$ as ptr, _  ' Section name 
    KeyName$ as ptr, _    ' Key name 
    structName as struct, _   ' Structure 
    size as ulong, _      ' Size of structure 
    inifile$ as ptr, ret as long
    WriteINIStruct = ret
end function

function GetINIStruct$(SectionName$,KeyName$,inifile$)
    ' Returns string value if nothing wrong or NULL if a problem
    'code by Richard Russell
    size = len(structName.struct) 
    calldll #kernel32, "GetPrivateProfileStructA", _ 
    SectionName$ as ptr, _  ' Section name 
    KeyName$ as ptr, _    ' Key name 
    structName as struct, _   ' Structure 
    size as ulong, _      ' Size of structure 
    inifile$ as ptr, ret as long
    if ret = 0 then GetINIStruct$ = "" : exit function
    GetINIStruct$ = structName.keychars$.struct
end function

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Richard Russell
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Re: struct type ptr
« Reply #29 on: Nov 22^nd, 2015, 8:03pm »

on Nov 22^nd, 2015, 12:21am, pnlawrence wrote:

Posted the following to the other forum

I trust you explained, in 'the other place', why you are using a STRUCT to store a string. I wouldn't want anybody to be misled into thinking it was preferable to using WritePrivateProfileString / GetPrivateProfileString (in normal circumstances).

Richard.

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